python - QTabWidget 的 PyQt 鼠标事件

Question

我想检测 QTabWidget 上的鼠标中键点击。我原以为 QWidget 上会有与鼠标事件相关的信号，但我看到的只是方法。

我是否需要对 QTabWidget 进行子类化，然后重写所述方法才能执行我想做的事情，还是我遗漏了什么？

Answer 1

您可以在 QTabBar 上安装事件过滤器(由 QTabWidget.tabBar() 返回)来接收和处理按下和释放事件，或者子类 QTabBar 重新定义mousePressEvent和mouseReleaseEvent，将QTabWidget的QTabBar替换为QTabWidget .setTabBar().

1. 使用事件过滤器的示例:

   class MainWindow(QMainWindow):
       def __init__(self):
           super(QMainWindow,self).__init__()
           self.tabWidget = QTabWidget(self)
           self.setCentralWidget(self.tabWidget)
           self.tabWidget.tabBar().installEventFilter(self)
           self.tabWidget.tabBar().previousMiddleIndex = -1           
   
       def eventFilter(self, object, event):
           if object == self.tabWidget.tabBar() and \
               event.type() in [QEvent.MouseButtonPress, 
                                QEvent.MouseButtonRelease] and \
               event.button() == Qt.MidButton: 
               tabIndex = object.tabAt(event.pos())
               if event.type() == QEvent.MouseButtonPress:
                   object.previousMiddleIndex = tabIndex
               else:   
                   if tabIndex != -1 and tabIndex == object.previousMiddleIndex:
                       self.onTabMiddleClick(tabIndex)                    
                   object.previousMiddleIndex = -1                        
               return True               
           return False
   
       # function called with the index of the clicked Tab
       def onTabMiddleClick(self, index):
           pass
   

2. 使用 QTabBar 子类的示例:

   class TabBar(QTabBar):
       middleClicked = pyqtSignal(int)
   
       def __init__(self):
           super(QTabBar, self).__init__()
           self.previousMiddleIndex = -1
   
       def mousePressEvent(self, mouseEvent):
           if mouseEvent.button() == Qt.MidButton:
               self.previousIndex = self.tabAt(mouseEvent.pos())
           QTabBar.mousePressEvent(self, mouseEvent)
   
       def mouseReleaseEvent(self, mouseEvent):
           if mouseEvent.button() == Qt.MidButton and \
               self.previousIndex == self.tabAt(mouseEvent.pos()):
               self.middleClicked.emit(self.previousIndex)
           self.previousIndex = -1
           QTabBar.mouseReleaseEvent(self, mouseEvent)
   
   
   class MainWindow(QMainWindow):
       def __init__(self):
           super(QMainWindow,self).__init__()
           self.tabWidget = QTabWidget(self)
           self.setCentralWidget(self.tabWidget)
   
           self.tabBar = TabBar()
           self.tabWidget.setTabBar(self.tabBar)
           self.tabBar.middleClicked.connect(self.onTabMiddleClick)
   
       # function called with the index of the clicked Tab
       def onTabMiddleClick(self, index):
           pass
   

(如果你想知道为什么这么简单的任务有这么多代码，点击被定义为一个按下事件，然后在大致相同的位置发生一个释放事件，所以按下的标签的索引必须是与发布的标签相同)。